As the development of antenna technologies, a large number of antennas may be arranged in a transmitting device. Three-dimensional beamforming technology of multiple antennas may improve antenna gains, and flexible configuration of beam widths and direction according to distribution of user equipments (UEs) may efficiently suppress white noises and inter-cell random interference and improve efficiency and reliability of system transmission, which is a hot candidate technology for future mobile communications systems.
For facilitating discovery and measurement by a UE, corresponding reference signals (RSs) are needed for guide, in which a channel state information reference signal (CSI-RS), a common reference signal (CRS), and a demodulation reference signal (DMRS), etc., are included.
Taking a CSI-RS as an example, the CSI-RS is defined in a long-term evolution (LTE) R10 system as being transmitted in a period and a fixed offset configured by the system. A base station may notify via high-layer signaling CSI-RS-Config which resource configuration and subframe configuration shall be adopted. Viewing from provisions in existing standards, when the base station configures resources of a CSI-RS via high-layer signaling, the base station will transmit the CSI-RS all the time according to corresponding periods and positions, unless the base station releases the resources of the CSI-RS again via high-layer signaling.
It should be noted that the above description of the background is merely provided for clear and complete explanation of this disclosure and for easy understanding by those skilled in the art. And it should not be understood that the above technical solution is known to those skilled in the art as it is described in the background of this disclosure.